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Con questo volume, che fa parte della collana BookMS Manuali (download dal sito www. centromicrozonazionesismica.it), intendiamo raccogliere, organizzare e mettere in condivisione i principali elementi e insegnamentitratti dall'intensa attività svolta in questi ultimi due anni. In particolare, sono riportate indicazioni utili alle attività di raccolta dati e relativa elaborazione per la realizzazione di carte di microzonazione sismica di livello3; si tratta di veri e propri protocolli per delineare procedure operative per la caratterizzazione delle Microzone Omogenee in Prospettiva Sismica (MOPS), la delimitazione delle Zone di Attenzione e la valutazione della Risposta Sismica Locale all'interno delle MOPS. In tal senso, si vuole sottolineare una volta di più il decisivo ruolo svolto dagli studi di microzonazione sismica quale strumento di mitigazione del rischio sismico, non solo nelle fasi post-evento, ma soprattutto nell'ambito di una lungimirante strategia di prevenzione che privilegi l'adozione di corrette scelte in sede di pianificazione e progettazione.

I terreni di copertura rappresentano un'importante porzione superficiale della litosfera, soprattutto in aree caratterizzate da evoluzione geologica neogenico-quaternaria, come il bacino mediterraneo.Tali terreni sono localizzati prevalentemente ai margini di bedrock affioranti, ossia in conche intramontane, fasce pedemontane, piane alluvionali e costiere, aree deltizie. Data la loro origine, sono costituiti da sedimenti sciolti o poco consolidati e da rocce tenere, che spesso fungono da terreni di fondazione per l'edilizia residenziale e industriale. Per loro natura e distribuzione, sono particolarmente soggetti ad hazard naturali, quali frane, inondazioni e allagamenti, amplificazioni sismiche, cedimenti, liquefazioni. Il loro studio riveste quindi notevole importanza per la mitigazione dei rischi naturali.Da anni l'IGAG investiga queste tipologie di terreni (ad esempio, con i Progetti Urbisit), soprattutto per studi di Microzonazione Sismica (MS), con approcci integrati di tipo geologico, geofisico e geotecnico per la definizione dei modelli di sottosuolo. L'approccio geologico è importante non solo per definire la geometria esterna dei depositi in relazione al bedrock, ma anche per ricostruire la struttura interna dei terreni investigati in termini di organizzazione stratigrafica dei litotipi affioranti e sepolti. I metodi utilizzati sono quelli della stratigrafia fisica, in particolare l'analisi di facies e la stratigrafia sequenziale per particolari contesti fluvio-costieri. Tali metodi permettono di definire l'architettura stratigrafica e la dinamica paleo-ambientale delle aree investigate, tramite l'identificazione delle litofacies e delle loro associazioni, l'individuazione e la gerarchizzazione di superfici limite, l'interpretazione di meccanismi e ambienti deposizionali (Miall, 2016). A tali fini, dati di affioramento, cartografici e di perforazione sono correlati tra loro e integrati con dati di letteratura, per investigare aree estense generalmente alcune decine di km2 e per profondità fino a 100 m. I prodotti derivati, elaborati nel Laboratorio GIS dell'IGAG Montelibretti, costituiscono carte geologiche e sezioni a grande scala (>=1:10.000), pannelli di correlazione e schemi di dettaglio dei rapporti stratigrafici. Essi sono alla base di tutte le elaborazioni successive per lo studio dei geohazard, ad esempio per la produzione di carte geo-tematiche (Carte MOPS, Carte MS), per la parametrizzazione geotecnica e idrogeologica del sottosuolo tramite correlazione litofacies-unità geotecniche (Mancini et al., 2014), per il supporto alla modellazione degli effetti di sito, per la pianificazione di campagne di indagine geofisica, geotecnica e idrogeologica. Aree test di applicazione di questo approccio sono il bacino romano e aree recentemente soggette a sismi (L'Aquila, Amatrice, Ischia), con prospettiva di applicazione ad aree urbane di Georgia e Albania (Accordi Bilaterali CNR).

The Central Italy earthquake sequence nominally began on 24 August 2016 with a M6.1 event on a normal fault that produced devastating effects in the town of Amatrice and several nearby villages and hamlets. A major international response was undertaken to record the effects of this disaster, including surface faulting, ground motions, landslides, and damage patterns to structures. This work targeted the development of high-value case histories useful to future research. Subsequent events in October 2016 exacerbated the damage in previously affected areas and caused damage to new areas in the north, particularly the relatively large town of Norcia. Additional reconnaissance after a M6.5 event on 30 October 2016 documented and mapped several large landslide features and increased damage states for structures in villages and hamlets throughout the region. This paper provides an overview of the reconnaissance activities undertaken to document and map these and other effects, and highlights valuable lessons learned regarding faulting and ground motions, engineering effects, and emergency response to this disaster.

Following the 2016 Mw 7.8 Kaik?ura earthquake, the report presents the central Wellington 3D basin model and low amplitude natural site period and NZS 1170.5 site subsoil class maps update for central Wellington.

The paper presents the main results of 1D/2D site response numerical analysesat 4 sites selected among the 137 municipalities of the Seismic Microzonation study which hasbeen carried out after the 2016 Central Italy seismic sequence. Complex site effects at ridge/slope crest and at the edge of slope covers lead to 2D aggravation factors in the range 2-3 withrespect to ground motion predicted with simple 1D analyses. A systematic comparison carriedout for all 137 municipalities, between computed and Italian code NTC18 amplification fac-tors highlighted that the code is generally conservative at low-to-medium periods and over-conservative at medium-to-high periods. A strategy for the use of microzonation site responseanalyses in support of seismic design for the reconstruction process is finally suggested .

During the Mw 6.0 Amatrice earthquake, which struck Central Italy on the 24th August 2016, the accelerometric station IT.AMT, located at about 10km from the epicentre recorded the highest values of the ground motion (Peak Ground Acceleration of the east component reached 0.87 g). Was IT.AMT station affected also by local soil conditions? To understand the role played by the site effects in the ground motion observed at AMT, we performed a detailed geological - geotechnical characterization of the site. Then, numerical analyses of seismic site response were carried out using 2D approaches. In parallel, several analysis were also performed on seismic records, to infer empirical amplification functions, used to compare the results of the numerical simulations. This study was partially supported by the Italian Department of Civil Protection (DPC) of the Presidency of Council of Ministers. The INGV-CNR IGAG collaboration made possible the realization of this multidisciplinary study, which includes detailed seismological, geological and geophysical analyses.

The central Italy earthquakes occurred on 26 and 30 October 2016. The Italy-US GEER team effort combines traditional reconnaissance activities of on-ground recording and mapping of field conditions, with advanced imaging and damage detection routines enabled by state-of-the-art geomatics technology. We describe preliminary findings useful for the broad technical community, emergency responders, and general public. These findings concern attributes of the causative fault system, surface fault rupture, recorded ground motions, landslides and rockfalls, damage to building structures and their spatial patterns, and damage to other types of structures, including bridges.

A geological survey has been carried out in the area of Amatrice, the most damaged town after the 24 August 2016 event, to provide a basic reference for geophysical and geotechnical data useful for seismic response analyses and microzonation studies. The morphologies and the stratigraphic-structural setting of the investigated area are detailed on a 1:5000 scale geological map and cross sections, which derive from the integration of field-based observations and photo-geological interpretation. The Amatrice basin is filled by the one km-thick Laga Formation, composed of Messinian syn-orogenic marine sandstones and siltstones (Marini et al., 2015) and covered with disconformity by Quaternary conglomerates and sands, referred to alluvial fans, fluvial terraces and landslides. Presently, the Amatrice basin is a structurallycontrolled depression bounded eastward by the Gorzano Mt ridge, and westward by the Sibillini Mts thrust front (Koopman, 1983). Our observations focus on (i) relationships between geometry and extent of cover deposits, (ii) bedding of the substratum, and (iii) areal arrangement and distribution of the main fault systems. Amatrice is located on a N-S trending mesa bounded by steep escarpments. The siliciclastic substratum was folded by syn-orogenic movements, broadly forming a NW-SE-trending synform, and is dissected by two main fault systems of the Plio-Quaternary post-orogenic tectonics. The first system consists of N-S striking high angle normal fault segments, each one having continuous length of up to 2 km; the second consists of E-W-striking normal-to-strike slip fault systems dissecting the first one. N-S-striking faults are morphologically expressed by fault plane scarps and triangular facets, and control the areal distribution of the Quaternary fluvial deposits. These are up to 50 m thick below Amatrice and thin to few metres along the north west direction. East of Amatrice, the stratigraphic setting is dominated by SW-prograding alluvial fans, downlapping the substratum, while on the West the stratigraphic setting is strongly complicated by large scale deformations (folding and tectonic repetitions) produced by shortening mechanisms. The recognized morphological irregularities, stratigraphic heterogeneities, and structural alignments are considered critical elements to define, at local scale, subsoil models useful for evaluating seismic amplification effects.

This work deals with the assessment of local seismic response in the explosive volcanic settings by reconstructing the subsoil model of the Stracciacappa maar (Sabatini Volcanic District, central Italy), whose pyroclastic succession records eruptive phases ended about 0.09 Ma ago. Heterogeneous characteristics of the Stracciacappa maar (stratification, structural setting, lithotypes, and thickness variation of depositional units) make it an ideal case history for understanding mechanisms and processes leading to modifications of amplitude-frequency-duration of seismic waves generated at earthquake sources and propagating through volcanic settings.

The Palatine hill archaeological area was investigated with the aim of assessing local geohazard levels. In particular, well-logs from continuous coring boreholes, Electrical Resistivity Tomography (ERT) and Ground Penetrating Radar (GPR) surveys were integrated in order to detect cavities, both in the geological units and in the anthropogenic layer. Continuous coring boreholes were drilled on the Palatine hilltop, along the slopes, and in the alluvial valleys bordering the hill. All the boreholes crossed the anthropic layer, which ranges in thickness between 1 and 20 meters. Some of the boreholes drilled built structures with empty voids, or filled by anthropogenic material. Several boreholes also crossed a network of tunnels dug in the tuff rocks underlying the anthropic layer. These tunnels are often filled with unconsolidated, unsorted anthropogenic material. For the GPR surveys, a GPR SIR3000 (GSSI) equipped with a 500 MHz bistatic antenna with constant offset, a 70 MHz monostatic antenna, and a 35 MHz monostatic antenna, was employed. A nominal microwave velocity of about 0.07 m ns-1 was determined from fitting hyperbolas to the raw field data and used to estimate the penetration depth from the GPR survey (up to approximately 15 meters). In order to obtain a planimetric image of all possible anomalous bodies, the time-slice representation technique was applied using all field profiles. GPR survey was than constrained mainly using well-logs and archaeological stratigraphies. Low intensity reflectors are related to fine-grained geological and anthropogenic materials, while high-intensity reflectors are referred to empty voids and to masonry or foundation remains. Resistivity field data were collected with a Syscal R2 resistivity meter coupled to a multielectrode acquisition system (48 electrodes), using different array configurations (Wenner-Schlumberger and Dipole-Dipole) and an electrode spacing ranging from 1 to 10 m, obtaining different investigation depth (from about 8 to 80 m). The electrical images were successively compared and calibrated with data coming from geological, archaeological, well-logs and GPR surveys. As regards the archaeological layer, it shows an irregular lower boundary and variable resistivity values. Relatively high resistivity values (?>400 ?m) are associated to voids and/or cemented conglomeratic walls, while low to moderate resistivity values (? Particular attention was paid to two areas of the hill, i.e., the Clivo Palatino and the so-called No Man's Land. Integration of information resulting from different prospecting techniques have allowed us to define an extremely complex subsoil setting, mainly due to the presence of cavities whose partial collapse has probably involved built structures already in historical times, as well documented by the archaeologists in this area of the hill.

Event Overview and Organization of Reconnaissance Activities,Overview of Reconnaissance Activities, Regional Faults and Seismic Source,Ground Motions, Landslides and Rockfalls, Performance of Building Structures and Damage Patterns,Performance of Bridge Structures, Other Infrastructure Systems, Lessons Learned and Next Steps

Correlation among borehole, outcrop, electrical resistivity tomography and ground penetrating radar data from a campaign of drilling and geophysical survey has allowed to reconstruct with detail the subsoil structure of the Palatine hill and Foro Romano (Rome, Italy), concerning both the natural geological substratum and the overlying anthropogenic cover (Mancini et al. 2014; Moscatelli et al. 2014). In the investigated area, several incised valleys and interfluves made of fluvial sediments and pyroclastites, overlaying the geological bedrock of Rome (i.e., Monte Vaticano Fm.), are detected below the anthropogenic deposits (masonry and infilled ground). A 3D model of the subsoil of the study area is presented here, obtained through the following three steps. 1) Production of 11 cross sections and a geological map (scale 1:2.000) with GIS software. 2) Selection of six relevant key horizons (i.e., basal unconformities of fluvial origin, bases of pyroclastic flow units, base of anthropogenic unit), that bound groups of stratigraphic units having similar lithotechnical features and parameters for numerical simulation oriented to seismic responses analyses. 3 The resulting 3D model shows geometries and spatial distribution of the geological bodies highlighting buried valleys where 2D amplification effects were calculated (Pagliaroli et al. 2014). The aim of 3D reconstruction is to provide a base for an advanced 3D numerical modelling of amplifications to be compared with the 2D simulation results.